The bulk Hamiltonian of the most general form is constructed using the method
known as the method of invariants, or \(k\cdot p\)  method [1]}, [2]},
well-developed for “conventional” spatial and time-reversal \(\mathcal {T}_\pm \)  symmetries.
The method can be straightforwardly adapted to other, more abstract symmetries, such as chiral \(\mathcal {S}\)  and charge-conjugation \(\mathcal {C}_\pm \) .
